The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 14, 1978
Filed:
Feb. 10, 1977
John P Jenkins, Towanda, IL (US);
International Tapetronics Corporation, Bloomington, IL (US);
Abstract
Solenoid has a coil which when energized moves a plunger inwardly through an opening in the housing against an external biasing spring which moves the plunger outwardly when the coil is deenergized. The front end wall of the housing has a plurality of bores disposed radially to the axis of movement of the plunger, each having a ferrous guide sleeve with an open end adjacent the plunger and a loose magnetic steel ball which is freely movable therein toward the plunger when the coil is energized. The plunger has an external groove within which the balls are seated when the plunger is in a fully retracted position. This enables the balls to extend from the open inner ends of the guide sleeves into latching positions holding the solenoid against outward movement. A much smaller electric power input is required in the coil to hold the balls in latched position, and therefore hold the plunger in retracted position, than is required to move the plunger to that position in the first place. One automatic control means is illustrated, using as an example a tape transport mechanism employing the improved solenoid, for reducing the electric current input to the coil automatically after the plunger is latched in the fully retracted position.